Guest Post: Soil Biological Health and Increased Nutrient Cycling

Guest Post: Soil Biological Health and Increased Nutrient Cycling

In agriculture, organic matter plays a crucial role in soil health. Organic matter only accounts for 5 percent of most agricultural soils. This tiny percent of your soil's structure is the difference between dead dirt and living, thriving soil with microorganisms, earthworms, and soil structure that allows for water and nutrient retention.

In the form of plant and animal residues, organic matter serves as sustenance for a myriad of soil microbes pivotal to nutrient cycling, bolstering the resilience of crops against various stresses. As extreme climate events become more common, it’s important to consider ways to make your farm more resilient.

The life cycles of fungi, bacteria, and a host of other soil dwellers are intertwined. Their preferred habitat is a relatively undisturbed area with an abundance of organic matter. That means crop residues on the soil surface and plant roots in the soil. Cover crops keep the microbial community fed between cash crops while decreasing erosion.

As the evidence mounts for the need to reduce the long-term use of synthetic fertilizers and the rise of sustainable farming practices, the push toward understanding the impact of soil biology on robust soil ecosystems has never been greater.

Benefits of Soil Microbes for Soil Health

Rich, fertile soil forms the bedrock of prosperous farming, yet this precious resource demands careful stewardship to maintain its vitality.

The vast majority of soil organisms are located in the top 6 inches of soil. Those microorganisms orchestrate nutrient cycling, transforming organic matter into life-fostering compounds. Crops are dependent on the enzymes released by microbial activity to achieve optimum growth.

Some modern agriculture practices have reduced this relationship with the addition of synthetic fertilizers and pesticides. Nutrient cycles are less efficient and erosion removes over 5 tons/acre of topsoil yearly, taking with it the nutrients applied. (1)  The NRCS data shows erosion rates have decreased over time, but they also show that when crop prices are high there is more erosion. Short-term cash crop gain for long-term soil fertility loss.

This is not an efficient or profitable way to farm.

Farming practices that nourish the soil biome reduce the dependence on synthetic fertilizers and steer agriculture toward a more sustainable horizon. The use of cover crops, crop rotations, and no-till all increase beneficial soil microbial communities. These farming systems are becoming more common throughout the United States.

With the loss of topsoil, and with it the beneficial microorganisms and nutrients, erosion is leaving many farmers with no option but to add more synthetics. However, the erosion pattern can be reversed while maintaining high yields.

Using sustainable farming methods significantly enhances the soil’s structure and porosity. This is good news for clay to sandy soil, and everything in between. Nutrients are cycled more efficiently with the aid of soil microbes that are minimally disturbed,

Enhancing Soil Structure and Porosity With Biologicals

Soil-dwelling organisms breathe life into the soil’s framework. However, most beneficial microorganisms, especially mycorrhizal fungi, can’t handle modern tillage or synthetics. Cultivated land is predominantly bacterial because of past farming practices. But dig a shovel of soil from the surrounding hedgerows or woods and you’ll find an abundance of earthworms, mycelium from fungi, and a soil structure that is crumbly and rich. The organic material in the undisturbed soil is a hospitable environment, enabling microorganisms, fungi, and bacteria to thrive and effectively break down organic compounds into the soil.

That friable soil structure and the large beneficial microbial community help to efficiently cycle nutrients. The nutrients remain in the root zone because microorganisms also use the same nutrients as plants, releasing nutrients as they die or are eaten by larger microorganisms.

As the biological processes intensify, the soil’s structure is transformed, becoming more friable and creating spaces for air and water to circulate. Such enhancements ensure that roots expand with less resistance, allowing crops to access a bounty of nutrients and water.

So, if you use no-till and maintain a large microbial population, you’ll have less leaching of nutrients.

Your fields, unlike the nearby woods, don’t have such a hospitable environment for efficient microbial processes. That means the soil structure is prone to compaction, leaching, or salinization. A study of Iowa soils and corn yield showed a clear relationship between lower corn yield and decreased depth of topsoil. (2) The drop in yield was much greater for tilled than no-till fields.

One aspect of soil fertility is porosity. We tend to think of this as an attribute of soil type. But sandy soil can become sandy loam over time. And clay can become clay loam over time.

Bolstering Water Retention in Sandy Soils Naturally

Sandy soils, notorious for their rapid drainage and low water-holding capacity, can pose a considerable challenge to the farmer’s quest for lush crops. The use of sustainable farming practices allows strong beneficial biological communities to create a natural alchemy, weaving together soil mineral particles and creating minute reservoirs that capture moisture, which would otherwise disappear into the depths.

This subtle transformation, catalyzed by the integration of organic matter, not only preserves precious water but also serves as a wellspring for microorganisms. As tiny architects, these organisms amend the soil matrix, further enhancing its ability to cradle life-giving droplets amidst arid conditions.

The Role of Microorganisms in Plant Nutrient Uptake

Microorganisms do much more than simply enrich the soil.

They act as a gradual dispenser of nutrients, essential for the growth and health of plants.

Organic matter, when broken down by the teeming life within the soil, releases nutrients at a pace that aligns with plant needs.

In tandem, it stimulates the bustling microbial life in the rhizosphere, the region surrounding plant roots, which is vital for robust growth.

This reciprocal relationship between soil health and plant vigor is at the heart of a flourishing ecosystem, anchoring the harmony between microorganisms and plant roots in the continuous cycle of life.

Facilitating the Slow Release of Essential Nutrients

The gradual breakdown of organic compounds by a strong community of beneficial fungi and bacteria yields a steady stream of food for plants. This measured release mirrors the natural rhythm of plant growth, ensuring a consistent supply of nitrogen, phosphorus, and potassium along with a suite of micro-nutrients vital for plant development.

Through the intricate dance of decomposition and nutrient release, organic matter acts as a slow-release fertilizer. This process eliminates the shocks to the system that can occur with synthetic fertilizers, promoting an even, sustainable growth pattern in crops without the risk of nutrient burn or rapid leaching.

Boosting Beneficial Microbial Activity in the Rhizosphere

Organic matter serves as a dynamic stage where essential soil bacteria and fungi flourish. By secreting enzymes and organic acids, these microorganisms break down complex organics, liberating nutrients near plant roots and fostering the rich tapestry that is the rhizosphere.

This microbial heaven directly impacts plant health, driving efficient nutrient absorption and bolstering plants’ resistance against pathogens. Such a boost in microorganism populations and nutrient cycling efficiency underscores the symbiotic relationships between soil and plant life and ecosystem resilience.

Attracting Earthworms and Other Soil Builders

The allure of crop residues and other plant debris draws earthworms and numerous soil architects, setting the stage for an enriched subterranean ecosystem. Organic materials act like a beacon, inviting these industrious workers to aerate the soil and foster natural soil structure, crucial for plant growth. Earthworm activity generates a more robust soil food web that feeds plant roots.

Enriching the soil with organic inputs, farmers foster an environment ripe for the proliferation of earthworms and other beneficial organisms. Their activity within the soil is a testament to the health of the land, indicative of a dynamic, living system brimming with potential.

Embracing sustainable practices invites these soil builders, along with their microbial counterparts, to converge, turning the soil into a crucible of life that supports robust crop yields and ecosystem resilience.

Contact our team at ST Biologicals. We are here to help you succeed. Soil speaks; we listen.

  1.  The state of erosion on U.S. farms (
  2. (PDF) Soil Erosion, Crop Productivity and Cultural Practices (